RE: Saito 82a vs 82b
The 82B has the cam setting down inside the crankcase with a almost flat cover acrossd the top
The 82A has the cam within a cover that sits on top of the crancase.
It is the same cam in the same place - it is just a matter of how it looks to the eye.
The "A" version crankcase will break at the junction between the cylinder and cam box in a bad crash that catches on the cylinder,
I don't see that it makes a lot of difference for repairing crashed Saitos, one that hit that bad is pretty well done for anyway.
This all started with a redesign of the Saito 82 into becoming the FG-14 gasoline engine. The then went back and changed the 82 and 72 glow engines to have a crankcase like the FG-14. The crankcase is common between the 72 and 82 anyway except for the number on the side.